/usr/lib/python2.7/dist-packages/nacl/bindings/crypto_box.py is in python-nacl 1.0.1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 | # Copyright 2013 Donald Stufft and individual contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import, division, print_function
from nacl._sodium import ffi, lib
from nacl.exceptions import CryptoError
__all__ = ["crypto_box_keypair", "crypto_box"]
crypto_box_SECRETKEYBYTES = lib.crypto_box_secretkeybytes()
crypto_box_PUBLICKEYBYTES = lib.crypto_box_publickeybytes()
crypto_box_NONCEBYTES = lib.crypto_box_noncebytes()
crypto_box_ZEROBYTES = lib.crypto_box_zerobytes()
crypto_box_BOXZEROBYTES = lib.crypto_box_boxzerobytes()
crypto_box_BEFORENMBYTES = lib.crypto_box_beforenmbytes()
def crypto_box_keypair():
"""
Returns a randomly generated public and secret key.
:rtype: (bytes(public_key), bytes(secret_key))
"""
pk = ffi.new("unsigned char[]", crypto_box_PUBLICKEYBYTES)
sk = ffi.new("unsigned char[]", crypto_box_SECRETKEYBYTES)
rc = lib.crypto_box_keypair(pk, sk)
assert rc == 0
return (
ffi.buffer(pk, crypto_box_PUBLICKEYBYTES)[:],
ffi.buffer(sk, crypto_box_SECRETKEYBYTES)[:],
)
def crypto_box(message, nonce, pk, sk):
"""
Encrypts and returns a message ``message`` using the secret key ``sk``,
public key ``pk``, and the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce size")
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
padded = (b"\x00" * crypto_box_ZEROBYTES) + message
ciphertext = ffi.new("unsigned char[]", len(padded))
rc = lib.crypto_box(ciphertext, padded, len(padded), nonce, pk, sk)
assert rc == 0
return ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
def crypto_box_open(ciphertext, nonce, pk, sk):
"""
Decrypts and returns an encrypted message ``ciphertext``, using the secret
key ``sk``, public key ``pk``, and the nonce ``nonce``.
:param ciphertext: bytes
:param nonce: bytes
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce size")
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
padded = (b"\x00" * crypto_box_BOXZEROBYTES) + ciphertext
plaintext = ffi.new("unsigned char[]", len(padded))
if lib.crypto_box_open(plaintext, padded, len(padded), nonce, pk, sk) != 0:
raise CryptoError("An error occurred trying to decrypt the message")
return ffi.buffer(plaintext, len(padded))[crypto_box_ZEROBYTES:]
def crypto_box_beforenm(pk, sk):
"""
Computes and returns the shared key for the public key ``pk`` and the
secret key ``sk``. This can be used to speed up operations where the same
set of keys is going to be used multiple times.
:param pk: bytes
:param sk: bytes
:rtype: bytes
"""
if len(pk) != crypto_box_PUBLICKEYBYTES:
raise ValueError("Invalid public key")
if len(sk) != crypto_box_SECRETKEYBYTES:
raise ValueError("Invalid secret key")
k = ffi.new("unsigned char[]", crypto_box_BEFORENMBYTES)
rc = lib.crypto_box_beforenm(k, pk, sk)
assert rc == 0
return ffi.buffer(k, crypto_box_BEFORENMBYTES)[:]
def crypto_box_afternm(message, nonce, k):
"""
Encrypts and returns the message ``message`` using the shared key ``k`` and
the nonce ``nonce``.
:param message: bytes
:param nonce: bytes
:param k: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce")
if len(k) != crypto_box_BEFORENMBYTES:
raise ValueError("Invalid shared key")
padded = b"\x00" * crypto_box_ZEROBYTES + message
ciphertext = ffi.new("unsigned char[]", len(padded))
rc = lib.crypto_box_afternm(ciphertext, padded, len(padded), nonce, k)
assert rc == 0
return ffi.buffer(ciphertext, len(padded))[crypto_box_BOXZEROBYTES:]
def crypto_box_open_afternm(ciphertext, nonce, k):
"""
Decrypts and returns the encrypted message ``ciphertext``, using the shared
key ``k`` and the nonce ``nonce``.
:param ciphertext: bytes
:param nonce: bytes
:param k: bytes
:rtype: bytes
"""
if len(nonce) != crypto_box_NONCEBYTES:
raise ValueError("Invalid nonce")
if len(k) != crypto_box_BEFORENMBYTES:
raise ValueError("Invalid shared key")
padded = (b"\x00" * crypto_box_BOXZEROBYTES) + ciphertext
plaintext = ffi.new("unsigned char[]", len(padded))
if lib.crypto_box_open_afternm(
plaintext, padded, len(padded), nonce, k) != 0:
raise CryptoError("An error occurred trying to decrypt the message")
return ffi.buffer(plaintext, len(padded))[crypto_box_ZEROBYTES:]
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